Generally in image display apparatuses such as projectors, image processing for changing the size of image information that is input in various sizes to a predetermined size is performed. In recent years, techniques have been disclosed in which when the size change processing described above is performed, image processing on the input image is performed using a plurality of image processing devices.
As such techniques for example, a technique has been disclosed in which a first resolution converting unit that converts an input image into a fixed resolution-converted image having a resolution equal to at least a horizontal resolution of fixed resolutions and outputs the image, and a second resolution converting unit that converts the fixed resolution-converted image output from the first resolution converting unit into a display resolution-converted image having a desired resolution and outputs the image are provided (for example, refer to Japanese Patent Publication No. 2008-298948).
Another technique has been disclosed in which a scaler unit that converts input signals into an output video format set in advance, and a scaler unit that compares a video region size with the current video format and performs enlargement or reduction processing on signals in the video region to obtain a proper size to thereby output the signals to a display device unit are provided (for example, refer to Japanese Patent Publication No. 2008-096806).
In both of the techniques disclosed in Japanese Patent Publication No. 2008-298948 and Japanese Patent Publication No. 2008-096806, the size change processing is performed on an image using two image processing devices. However, in a case where, for example, position adjustment processing for moving an image in the horizontal direction or the vertical direction is performed, when the position adjustment is performed by an image processing device on the primary side, the burden on the image processing device on the primary side is increased because the image processing device on the primary side performs the size change processing and position adjustment processing on an image. Therefore, this results in a problem that an expensive image processing device with high processing speed has to be used. When the position adjustment is performed by an image processing device on the secondary side, the burden on the image processing device on the primary side can be reduced. However, when the position adjustment of an image is performed, image information originally required is missing, which results in a problem that a proper position adjustment cannot be performed.